/*! @file Defines `boost::hana::not_`. @copyright Louis Dionne 2013-2016 Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt) */ #ifndef BOOST_HANA_NOT_HPP #define BOOST_HANA_NOT_HPP #include <boost/hana/fwd/not.hpp> #include <boost/hana/concept/constant.hpp> #include <boost/hana/concept/logical.hpp> #include <boost/hana/config.hpp> #include <boost/hana/core/to.hpp> #include <boost/hana/core/dispatch.hpp> #include <boost/hana/detail/canonical_constant.hpp> #include <type_traits> BOOST_HANA_NAMESPACE_BEGIN //! @cond template <typename X> constexpr decltype(auto) not_t::operator()(X&& x) const { using Bool = typename hana::tag_of<X>::type; using Not = BOOST_HANA_DISPATCH_IF(hana::not_impl<Bool>, hana::Logical<Bool>::value ); #ifndef BOOST_HANA_CONFIG_DISABLE_CONCEPT_CHECKS static_assert(hana::Logical<Bool>::value, "hana::not_(cond) requires 'cond' to be a Logical"); #endif return Not::apply(static_cast<X&&>(x)); } //! @endcond template <typename L, bool condition> struct not_impl<L, when<condition>> : hana::default_ { template <typename ...Args> static constexpr auto apply(Args&& ...) = delete; }; template <typename L> struct not_impl<L, hana::when<std::is_arithmetic<L>::value>> { template <typename Cond> static constexpr Cond apply(Cond const& cond) { return static_cast<Cond>(cond ? false : true); } }; namespace detail { template <typename C, typename X> struct constant_from_not { static constexpr auto value = hana::not_(hana::value<X>()); using hana_tag = detail::CanonicalConstant<typename C::value_type>; }; } template <typename C> struct not_impl<C, hana::when< hana::Constant<C>::value && hana::Logical<typename C::value_type>::value >> { template <typename Cond> static constexpr auto apply(Cond const&) { return hana::to<C>(detail::constant_from_not<C, Cond>{}); } }; BOOST_HANA_NAMESPACE_END #endif // !BOOST_HANA_NOT_HPP